60–70% of YC X25 Agent Startups Are Using TypeScript

Jun 9, 2025 · 1 min read

I recently saw a tweet from Sam Bhagwat (Mastra AI's Founder) which mentions that around 60–70% of YC X25 agent companies are building their AI agents in TypeScript.

This stat surprised me because early frameworks like LangChain were originally Python-first.

So, why the shift toward TypeScript for building AI agents?

Here are a few possible reasons I’ve understood:

Many early projects focused on stitching together tools and APIs. That pulled in a lot of frontend/full-stack devs who were already in the TypeScript ecosystem.
TypeScript’s static types and IDE integration are a huge productivity boost when rapidly iterating on complex logic, chaining tools, or calling LLMs.
Also, as Sam points out, full-stack devs can ship quickly using TS for both backend and frontend.
Vercel's AI SDK also played a big role here.

I would love to know your take on this!

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Also published on DEV.to.

I recently saw a tweet from Sam Bhagwat (Mastra AI's Founder) which mentions that around 60–70% of YC X25 agent companies are building their AI agents in TypeScript.

This stat surprised me because early frameworks like LangChain were originally Python-first.

So, why the shift toward TypeScript for building AI agents?

Here are a few possible reasons I’ve understood:

Many early projects focused on stitching together tools and APIs. That pulled in a lot of frontend/full-stack devs who were already in the TypeScript ecosystem.
TypeScript’s static types and IDE integration are a huge productivity boost when rapidly iterating on complex logic, chaining tools, or calling LLMs.
Also, as Sam points out, full-stack devs can ship quickly using TS for both backend and frontend.
Vercel's AI SDK also played a big role here.

I would love to know your take on this!